Which Numidian king's defection helped Rome win Zama?

Masinissa, also spelled Massinissa, Massena and Massan, was an ancient Numidian king best known for leading a federation of Massylii Berber tribes during the Second Punic War, ultimately uniting them into a kingdom that became a major regional power in North Africa. Much of what is known about Masinissa comes from Livy's History of Rome, and to a lesser extent Cicero's Scipio's Dream. As the son of a Numidian chieftain allied to Carthage, he fought against the Romans in the Second Punic War, but later switched sides upon concluding that Rome would prevail. With the support of his erstwhile enemy, he united the eastern and western Numidian tribes and founded the Kingdom of Numidia. As a Roman ally, Masinissa took part in the decisive Battle of Zama in 202 BC that effectively ended the war in Carthage's defeat; he also allowed his wife Sophonisba, a famed Carthaginian noblewoman who had influenced Numidian affairs to Carthage's benefit, to poison herself in lieu of being paraded in a triumph in Rome.